Printing inks and coatings compositions for polyethylene coated board

ABSTRACT

The present invention provides a printing ink or coating composition comprising a self-crosslinking acrylic polymer, a coalescent and a silicone emulsion wherein the self-crosslinking acrylic polymer has a glass transition temperature of greater than 25° C. Furthermore the present invention also provides a process for preparing a coated substrate, in particular a polyboard substrate and an article made from the coated substrate, such as a milk or juice carton.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/039,560 filed Aug. 20, 2014, which is hereby incorporatedherein by reference in its entirety and for all purposes.

FIELD OF THE INVENTION

The present invention is directed to water-based inks and coatingcompositions for printing onto polyboard substrates which are primarilyused for milk and juice cartons which are free of Bisphenol A (BPA) andpolymers comprising BPA.

BACKGROUND OF THE INVENTION

Presently, water-based inks used for printing onto polyboard substratesprimarily used for milk and juice cartons and other paper/boardsubstrates are based on epoxy esters which contain Bisphenol A (BPA) andpolymers comprising BPA. However, due to suspected toxicity, regulationsare changing such that these inks can no longer contain Bisphenol A andpolymers comprising BPA.

Consequently, there is a requirement to provide water-based inks forgeneral printing, and in particular, for flexographic and gravureprinting for polyboard substrates, that exhibit acceptable performanceand do not contain Bisphenol A (BPA) and polymers comprising BPA.

WO 0073392 discloses the use of hybrid alkyd acrylic resins in inks foruse on polythene coated board used for milk cartons.

US2009/0297796 discloses water based screen printing inks that may besuitable for other printing methods, primarily containing specialistpigments and a cross linker.

U.S. Pat. No. 7,807,739 discloses an aqueous composition for coatingsubstrates comprising a cross linkable polymer, an acrylic polymer andan epoxysilane.

US2013/0309516 is directed to a coating composition having an acrylicpolymer with a low glass transition temperature that contains a crosslinkable functional group and a cross linking agent.

JP3301267 is directed to water color inks containing a resin for use oncorrugated fiberboard.

Finally, CN101812255 is directed to an ink containing an acrylic resinfor use on a high temperature resistance carton.

SUMMARY OF THE INVENTION

The present invention provides a printing ink or coating compositioncomprising

-   -   a) at least one self-crosslinking acrylic polymer,    -   b) at least one coalescent and    -   c) at least one silicone emulsion        wherein the self-crosslinking acrylic polymer has a glass        transition temperature (T_(g)) of greater than 0° C.

Furthermore the present invention also provides a process for preparinga coated substrate, in particular a polyboard substrate, with the ink ora composition printed thereon which comprises

-   -   a) applying the printing ink or coating composition according to        the invention to a surface of the substrate and    -   b) drying the ink or composition.

These and other objects, advantages, and features of the invention willbecome apparent to those persons skilled in the art upon reading thedetails of the methods and formulations as more fully described below.

DETAILED DESCRIPTION OF THE INVENTION

It has now been found that a printing ink or coating compositioncontaining a self-crosslinking acrylic polymer, a coalescent and atleast one silicone emulsion can exhibit good adhesive properties alongwith the requisite resistance properties when the self-crosslinkingacrylic polymer has a glass transition temperature of greater than 0° C.

The glass transition temperature herein relates to the acrylic polymerprior to self-cross linking.

These printing inks or coating compositions are of low toxicity and arecapable of outperforming water-based inks that are based upon epoxyesters that contain Bisphenol A (BPA) and in particular, exhibitequivalent or better physical properties in terms of resistance to rub,water, milk, juice and line lubricant.

The printing ink or coating composition according to the presentinvention is substantially free of Bisphenol A (BPA) and isadvantageously substantially free of epoxy esters.

Furthermore, the printing inks and coating compositions are typicallywater-based which provides for improved pigment wetting. This enablesthe printing inks and coating compositions to contain less colorant thusallowing for higher amounts of varnish. This in turn provides formaximum resistance whilst retaining color strength.

Preferably, the self-crosslinking acrylic polymer has a glass transitiontemperature of between 20 to 70° C. and advantageously between 40 to 60°C.

The self-crosslinking acrylic polymer is usually in the form of anaqueous dispersion or emulsion and is typically the product of at leasttwo monomers that react with one another.

Furthermore, a self-crosslinking acrylic polymer refers to a one packacrylic that whilst under ambient cure, can achieve curing, typicallyvia a carbonyl/amine reaction. This can occur between ketone groups andbi- or polyfunctional amine compounds having groups that are reactivetowards carbonyl groups. These acrylic polymers exhibit enhancedresistance properties in the resultant dried film.

The cross-linking reaction, depending upon the acrylic type, may also beinitiated by the evaporation of water upon drying, a change of pH of thevehicle or by curing at elevated temperatures where the cross-linkingreaction occurs faster or the reactive groups are de-blocked.

One example of self-crosslinking is shown in GB-A-2045768, whichdescribes a dispersion which is based upon the emulsion polymerizationproduct of a monomer mixture primarily comprising lower alkyl(meth)acrylate monomers, minor amounts of (meth)acrylic acid andglycidyl (meth)acrylate.

Self-crosslinking acrylic polymers may include binders selected from thegroup consisting of styrene-acrylic ester copolymer, a styrene/acrylicester copolymer containing acrylamido groups and preferably a copolymerbased on acrylonitrile, methacrylamide and acrylic ester.

Preferably, the self-crosslinking acrylic polymer is formed fromreactive monomers which include at least one monomer selected frommethyl acrylic acid (MAA), methyl methacrylate (MMA), butyl acrylate,butyl methacrylate, styrene and methyl styrene. Advantageously theself-crosslinking polymer is a styrene/acrylic ester copolymer.

In a preferred embodiment, the polymer is produced via a carbonyl/aminereaction, and advantageously an acrylate with a pendent N-methylol group(such as NIBMA) is used.

Examples of commercial acrylates formed from such monomers includeAlberdingk AC2714VP, Synthomer AM00035, Organikkimyan Orgal P086V andDSM Neocryls XK12 & 14.

Usually, the printing ink or coating composition comprises between 20 to60 wt % of self-crosslinking acrylic polymer, preferably between 30 to50 wt % of self-crosslinking acrylic polymer and advantageously between20 to 40 wt % of self-crosslinking acrylic polymer.

Advantageously, the coalescent is also an acrylic emulsion and typicallyhas a glass transition temperature of less than 20° C., advantageouslyless than 0° C.

Examples of commercial coalescents include Dow Lucidene 605, DSM NeocrylA2095, and BASF Joncryl 8052.

Usually, the printing ink or coating composition comprises between 2 to20 wt % of coalescent and preferably between 5 to 15 wt % of coalescent.

The printing ink or coating composition also comprises a siliconeemulsion.

The addition of a silicone emulsion in the formulation helps to improvethe chilled wet rub. Examples of commercially available siliconesinclude Dow Corning DC84, DC 51, DC 209S, and Worleeadd 350. Thesesilicones are high molecular weight polydimethylsiloxane emulsion,containing reactive silanol groups. Alternatively a blocked reactivesilicone emulsions may be used.

Usually, the printing ink or coating composition comprises between 0.2to 3 wt % of silicone emulsion and preferably between 1 to 2 wt % ofsilicone emulsion.

The printing ink or coating composition may further comprise a colorant.Such colorants typically include organic and inorganic pigmentdispersions and dyes.

Typical pigment dispersions include Yellow 13; Orange 34; Red 122; Red184; Red 266; Black 15:3; Violet 23; Green 7; and Blue 15:3;

Usually, the printing ink or coating composition comprises a standardacrylic base containing a pigment dispersion, in the amount of between 1to 35 wt % and a varnish containing the self-crosslinking acrylicpolymer, the coalescent and the silicone emulsion according to thepresent invention in the amount of between 65 to 99 wt %.

Preferably, the printing ink or coating composition comprises between 5to 50 wt % of pigment dispersion, more preferably between 20 to 45 wt %of pigment dispersion and advantageously between 30 to 40 wt % ofpigment dispersion.

The printing ink or coating compositions typically contain otheradditives, which may include wetting aids, alcohols, polyethylene waxemulsions, wax dispersions, antifoams, ammonia, defoamers, dispersants,stabilizers, silicones, rheological modifiers, plasticizers and thelike.

Examples of such additives include isopropanol and n-propanol;polyethylene wax emulsions such as Munzing Lubraprint 2036 and BykAquacer 531; wax dispersions such as Munzing Lubraprint 499, KeimUltralube D816 and Crayvallac WW1001; antifoams such as Byk 023 andEvonik Tegofoamex 1488; and wetting aids such as Evonik TegoWet 500 andByk Dynwet 800.

The printing ink or coating composition according to the presentinvention may be used for any kind of printing but they areadvantageously gravure or flexographic printing inks or coatingcompositions.

The inks of the present invention have been formulated preferably foruse on polyethylene coated board substrates, e.g. polyboard, mainly usedas containers (e.g. milk and juice containers). Other substrates mayinclude corrugated paper, paper pre-corrugation, paper and generalboard.

In a particular embodiment of the invention the printing inks andcoating compositions are formulated such that they can successfullyadhere to a polyethylene layer and thus can be advantageously printeddirectly on “pre-formed” polyboard, as opposed to being printedinitially on the board. This eliminates the need for extrudingpolyethylene over the top of a coated board after printing.

The printing inks and coating compositions of the present invention alsopreferably have indirect food contact status, have been successfullymigration tested and all the materials used in therein are preferablyToxic Substances Control Act (TOSCA) and Food and Drug Administration(FDA) approved.

The present invention also provides a process for preparing a coatedsubstrate with an ink or a composition printed thereon which comprises

-   -   a) applying the printing ink or coating composition as herein        described above to a surface of the substrate and    -   b) drying the ink or composition.

Furthermore the present invention further provides articles, such asmilk and juice cartons formed from the coated substrate.

The invention is further described by the examples given below.

EXAMPLES Example 1. Formulation of Inks According to the PresentInvention

Red, blue, black and green inks containing the materials (in weightpercent) shown in table 1 were formulated.

TABLE 1 Ink 1 Ink 2 Ink 3 Ink 4 Typical Material (Red) (Blue) (Black)(Green) Range Neocryl XK14 Acrylic 39.7 39.7  39.7  39.7 20-60 emulsionJoncryl 8052 7.9 7.9 7.9 7.9  5-15 N-Propanol 2.9 2.9 2.9 2.9 1-5Aquacer 531 6.5 6.5 6.5 6.5  2-12 Crayvallac WW1001 5.2 5.2 5.2 5.2 2-10 Tego Foamex 1488 0.2 0.2 0.2 0.2 0.1-1.0 Dynwet 800 1.3 1.3 1.31.3 0.2-3.0 DC209S 1.3 1.3 1.3 1.3 0.2-3.0 Pigment Dispersion (Red) 35.0— — —  5-50 Pigment Dispersion (50/50 — 35.0  — — Cyan and Violet -Blue) Pigment Dispersion (Black) — — 35.0  — Pigment Dispersion (Green)— — — 35.0 Total wt % 100.0 100.0  100.0  100.0

Example 2. Formulation of Inks Containing Various Self-CrosslinkingAcrylic Polymers

Ink formulations containing the materials as shown in table 2 wereformulated wherein self-crosslinking acrylic polymers having varyingglass transition temperatures were incorporated therein.

TABLE 2 Compar- Compar- Ink 5 ative Ink 6 ative Ink 7 Ink 8 Ink 9Material Cyan Cyan Cyan Cyan Cyan Neocryl XK14 39.7 — — — — Acrylicemulsion (Tg 50° C.) Wallpol 01B — 39.7 — — — Acrylic Emulsion (Tg −18°C.) NeoRez R620 — — 39.7 — — Polyurethane Emulsion Orgal P086V — — —39.7 — Acrylic Emulsion (Tg 25° C.) Alberdingk AC2714VP — — — — 39.7Acrylic Emulsion (Tg 43° C.) Joncryl 8052 7.9 7.9 7.9 7.9 7.9 N-Propanol2.9 2.9 2.9 2.9 2.9 Aquacer 531 6.5 6.5 6.5 6.5 6.5 Crayvallac WW10015.2 5.2 5.2 5.2 5.2 Tego Foamex 1488 0.2 0.2 0.2 0.2 0.2 Dynwet 800 1.31.3 1.3 1.3 1.3 DC209S 1.3 1.3 1.3 1.3 1.3 Pigment Dispersion 35.0 35 3535 35 (Cyan) Total wt % 100.0 100.0 100.0 100.0 100.0

Example 3. Printing and Ink Testing

The inks having a print viscosity of 12 seconds, Zahn 3 cup were printedonto a treated polyethylene board and then tested and compared tocommercial inks containing Bisphenol A.

Table 3 shows the Satra rub resistance results, after 7 days ageing forthe inks according to the present invention as listed in table 1 andcommercial Flint Aquapak comparative epoxy ester inks.

TABLE 3 1% Saniglide Line lube H202 Resistance Chilled 3 Min. 3 Min.Chilled Wet Humid Wet Rub Drop Complete Drop Complete Rub Wet (SprayedInk Water Milk Juice Test removal Test removal (Immersed) Rub Print)Flint 100 70 30 8 15 8 15 30 30 40 Red Flint 70 50 30 8 25 8 25 25 30 30Blue Flint 30 40 40 6 10 7 15 10 20 10 Black Flint 60 40 20 7 15 7 25 2040 20 Green Ink 1 100 60 40 8 15 7 15 30 30 50 Red Ink 2 80 50 50 8 25 825 35 40 50 Blue Ink 3 60 40 40 8 15 7 15 10 20 30 Black Ink 4 100 60 407 15 7 25 20 50 20 Green

For the 3 min. Saniglide Line Lube and H₂O₂ Drop Test, 1 equates to poor(i.e. complete ink removal) whilst 10 equates to excellent (no inkremoval) after 5 rubs.

Rubbing was then carried out to complete removal and the number offurther rubs recorded. All the other tests record the number of rubsrequired for complete removal of the ink, a higher number of rubs beingindicative of better rub resistance.

These results show that the inks described in the invention requiredmore rubs for complete removal than for the present commerciallyavailable inks (Flint Aquapak), thus showing an improvement in overallresistance properties.

Example 4. Ink Testing for Inks Containing Self-Crosslinking AcrylicPolymers with Varying Glass Transition Temperatures

Table 4 shows the Satra rub resistance results for self-crosslinkingacrylic polymers with various glass transition temperatures.

TABLE 4 1% Saniglide Line lube H202 Resistance Chilled 3 Min. 3 Min.Chilled Humid Wet Rub Drop Complete Drop Complete Wet Rub wet (SprayedInk Water Milk Juice Test removal Test removal (Immersed) rub Print) Ink5 100 60 50 8 15 7 15 30 40 50 Ink 6 80 20 40 4 <5 4 <5 20 20 20 (comp)Ink 7 40 40 40 4 <5 4 <5 30 30 30 (comp) Ink 8 80 40 50 6 15 6 15 30 4040 Ink 9 80 40 50 6 15 6 15 30 40 40

It is shown below in Table 4 that when self-crosslinking acrylicpolymers with a Tg less than 0° C. are used the resistance propertiesare much lower than the inks according to the present invention.

Ink 5 having an acrylic polymer with a glass transition temperature of50° C. is preferred. However, ink 8 having a glass transitiontemperature of 25° C. and ink 9 having a glass transition temperature of43° C. also exhibit improved physical properties.

Example 5. Physical Properties of the Inks According to the PresentInvention Versus Comparative Commercial Inks

The inks were printed on polythene extruded board and the surfacetreated to 40-44 dynes/cm, using a commercial Flexo press at 750 ft/minusing a 360#, 6.0 cc/m2 volume anilox and photopolymer plate.

Table 5 shows that there is no deterioration of physical properties ofthe inks according to the present invention.

TABLE 5 Comparative Commercial Inks: Flint Other Testing Aquapak Inks1-4 Adhesion Tape Test - Immediate 100% 100% Scratch*- Immediate (HighForce) 10 (Black/ 10 (Black - 9) Blue - 8) Resolubility StandardEquivalent Wash-up Standard Equivalent Printability, Flexo* 9 10 Gloss(60° C.) - 7 days Red - 46.5, Red - 46.0, Blue - 38.9, Blue - 40.0,Black - 39.3, Black - 41.4, Green - 40.0 Green - 39.9 Static Slip - Faceto back - 16 days 0.26 0.25 Dynamic Slip - Face to back - 16 days 0.230.23 Static Slip - Face to face - 16 days 0.32 0.29 Dynamic Slip - Faceto face - 16 days 0.19 0.20 Blocking* - Face to Face - 16 days 10 10Blocking* - Face to Back - 16 days 10 10 Hand Wet Rub Test* 10 10 *10 =Excellent; 1 = Poor

Test Methods:

Printability (Flexo): Visual Assessment

Gloss (60°): Gloss meter reading.Wash Up: Assessment from print crewResolubility: Assessment from print crewScratch Resistance—Proof print is laid print-side up on a hard surfaceand back of index finger nail scratched across surface. Print isevaluated for level of ink removal.

Satra Wet Rub

Using a Satra rub tester (Model STM 461), a water soaked felt pad (25 mmOD) under a specified load (1.8 Kg) is rotated on the surface of theprint for 30 complete cycles. The print is examined for signs of inkremoval and/or surface damage.

Prints were air dried for 7 days. The prints were then tested for thefollowing reagents: Water, Milk, Orange Juice and Line lubricant(Saniglide) and hydrogen peroxide. For the line lubricant and H₂O₂, theline lubricant/H₂O₂ is placed on the print for three minutes and theprint is given 5 subsequent rubs and assessed on a grey scale. The inkis then further tested to complete removal.

Chilled/Humid Print and Subsequent Satra Rub Test:

Prints are placed in a bucket of water and refrigerated/placed in 50° C.humid conditions for 16 to 24 hours. A test was also been carried out byspraying the prints with water and then positioning leaving in a fridgefor 16 to 24 hrs. The procedure for Satra wet rub (water) was thenfollowed.

Hand Wet Rub Test:

Grasp proof print with thumb and forefinger at either side of the print,hands approx. 1″ apart, rotate vigorously for 50 cycles under runningwater, prints being face to face, to simulate repeated flexing of print.Assess level of ink removal and/or damage to print surface.

Adhesion Tape Test:

Apply Scotch 610 adhesive tape to the sample. Manually pull off the tape(slow, followed by fast pull) in a direction perpendicular to thesurface of the print. The tape is pulled off immediately once it hasbeen applied.

Blocking:

The samples are placed in the press as requested (face to face and/orface to back) and a pressure of 10 MPa is applied at room temperaturefor 10 minutes. The samples are visually inspected to ensure noblocking.

Slip Test Davenport Coefficient of Friction

Note: Using small sled for method ASTM D.1894—Speed 15cm/min./Sensitivity X5.

-   -   1. Produce proof prints of the batch under test on the specified        substrate(s). Print of sufficient width and length should be        prepared.    -   2. Affix one sample of print, minimum 10 inches long, to the        test bed with adhesive tape, ensuring it is held flat, smooth        and unstretched.    -   3. Cut another piece of print, using appropriate template, and        affix to the underside of the sled with adhesive tape. Ensure        that the print surface is not touched.    -   4. Attach the cord to the sled, and place the latter gently onto        the left-hand end of the print on the test bed, so that it is        positioned centrally between the two L-shaped marks, with its        leading edge in line with the right-hand edge of the marks.        Leave a small amount of slackness in the cord.    -   5. Press the ‘Start’ button (and if measuring static slip,        immediately re-set the digital display in order to ensure a        false reading is not registered from start-up).    -   6. Static: Record the final (maximum) reading on the digital        display, or the highest recorded force at the beginning of the        recorder trace.    -   7. Dynamic: Note the highest and lowest readings, during the        period of steady movement, on the needle scale, and record the        mean of these values. If using a recorder, obtain the average of        the trace during this period.

The coefficient of static and/or dynamic friction is given by:

${{Coefficient}\mspace{14mu} {of}\mspace{14mu} {Friction}} = \frac{{Force}\mspace{14mu} {in}\mspace{14mu} {grams}}{{Weight}\mspace{14mu} {of}\mspace{14mu} {sled}\mspace{14mu} {in}\mspace{14mu} {grams}}$

-   -   Where the force in grams=reading multiplied by 10 for        sensitivity X1 or =reading multiplied by 2 for sensitivity X5

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made, and equivalents may besubstituted, without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe invention.

1. A printing ink or coating composition comprising a) at least oneself-crosslinking acrylic polymer, b) at least one coalescent and c) atleast one silicone emulsion wherein the self-crosslinking acrylicpolymer has a glass transition temperature of greater than 0° C.
 2. Aprinting ink or coating composition according to claim 1 wherein theself-crosslinking acrylic polymer has a glass transition temperature ofbetween 20 to 70° C.
 3. A printing ink or coating composition accordingto claim 1 or 2 wherein the self-crosslinking acrylic polymer has aglass transition temperature of between 40 to 60° C.
 4. A printing inkor coating composition according to anyone of the preceding claimswherein the self-crosslinking acrylic polymer is formed from monomersselected from methyl acrylic acid (MAA), methyl methacrylate (MMA),butyl acrylate, butyl methacrylate, styrene and methyl styrene.
 5. Aprinting ink or coating composition according to anyone of the precedingclaims wherein the self-crosslinking polymer is a styrene/acrylic estercopolymer.
 6. A printing ink or coating composition according to anyoneof the preceding claims wherein the self-crosslinking polymer is formedfrom a carbonyl/amine reaction.
 7. A printing ink or coating compositionaccording to anyone of the preceding claims wherein theself-crosslinking polymer is an acrylic emulsion.
 8. A printing ink orcoating composition according to anyone of the preceding claims whereinthe coalescent has a glass transition temperature of less than 20° C. 9.A printing ink or coating composition according claim 8 wherein thecoalescent has a glass transition temperature of less than 0° C.
 10. Aprinting ink or coating composition according to anyone of the precedingclaims wherein the coalescent is an acrylic emulsion.
 11. A printing inkor coating composition according to anyone of the preceding claimswherein the silicone emulsion is high molecular weightpolydimethylsiloxane emulsion containing reactive silanol groups.
 12. Aprinting ink or coating composition according to anyone of the precedingclaims comprising between 20 to 60 wt % of self-crosslinking acrylicpolymer.
 13. A printing ink or coating composition according to anyoneof the preceding claims comprising between 30 to 50 wt % ofself-crosslinking acrylic polymer.
 14. A printing ink or coatingcomposition according to anyone of the preceding claims comprisingbetween 30 to 50 wt % of self-crosslinking acrylic polymer.
 15. Aprinting ink or coating composition according to anyone of the precedingclaims comprising between 2 to 20 wt % of coalescent.
 16. A printing inkor coating composition according to anyone of the preceding claimscomprising between 5 to 15 wt % of coalescent.
 17. A printing ink orcoating composition according to anyone of the preceding claimscomprising between 0.2 to 3 wt % of silicone emulsion.
 18. A printingink or coating composition according to anyone of the preceding claimscomprising between 1 to 2 wt % of silicone emulsion.
 19. A printing inkor coating composition according to anyone of the preceding claimsfurther comprising a colorant.
 20. A printing ink or coating compositionaccording to claim 19 wherein the colorant is a pigment dispersion. 21.A printing ink or coating composition according to claim 20 comprisingbetween 5 to 50 wt % of pigment dispersion.
 22. A printing ink orcoating composition according to claim 21 comprising between 20 to 45 wt% of pigment dispersion.
 23. A printing ink or coating compositionaccording to claim 22 comprising between 30 to 40 wt % of pigmentdispersion.
 24. A printing ink or coating composition according toanyone of the preceding claims further comprising one or more additivesselected from the group consisting of wetting aids, alcohols,polyethylene wax emulsions; wax dispersions; antifoams; waxes, ammonia,defoamers, dispersants, stabilizers, silicones, rheological modifiersand plasticizers.
 25. A printing ink or coating composition according toanyone of the preceding claims, wherein the composition is a gravure orflexographic printing ink or coating composition.
 26. A printing ink orcoating composition according to anyone of the preceding claims that iswater-based.
 27. A printing ink or coating composition according toanyone of the preceding claims which is substantially free of BisphenolA (BPA).
 28. A printing ink or coating composition according to anyoneof the preceding claims which is substantially free epoxyesters.
 29. Aprocess for preparing a coated substrate with an ink or a compositionprinted thereon which comprises a) applying the printing ink or coatingcomposition according to anyone of the preceding claims to a surface ofthe substrate and b) drying the ink or composition.
 30. A processaccording to claim 29 wherein the substrate is polyethylene board.
 31. Aprocess according to claim 29 wherein the substrate is corrugated paper.32. A process according to claim 29 wherein the substrate is apre-formed polyboard.
 33. A coated substrate prepared by the process ofanyone of claims 29 to
 32. 34. An article formed from the coatedsubstrate of claim
 33. 35. An article according to claim 34 in the formof a milk or juice carton.